K1818VG93
ZXNet echo conference «hardware.zx»
Hello Mick
Mic> Yesterday I wanted to start abusing my ZX-777, which
Mic> lay in the storage room for 7 years. So I turned it on to check
Mic> whether it works or not, it works, but! :confused:
Mic> I insert the floppy disk, but TRDOS writes that it is not there. And so it is with everyone. I think s
Mic> disk drive, what happened - I installed it on a PC - the disk drive works there.
Mic> So this is typical, the drive does not “grunt” when it starts zero
Mic> track search. There was such a glitch before, but it was a long time ago and I don’t remember why
Mic> matter.
Mic> The cable is also fine. Replacing the VG93 did not produce any results. Who is the thread
Mic> will tell you what the problem is. :o
On PC drives are installed with ID1 and then turning the cable over makes it
zero. I dare to suggest that if he earned money on the PC, this is not true
installed ID jumper.
Hello, vasstr
vas> On PC drives are installed with ID1 and then turn over the cable
vas> makes it null. I dare say that if he made money on
vas> there is an incorrectly set ID jumper.
No, the reason is banally simple - damn resistors on the drive.
I juggled the drive on a PC and forgot about them. And then I remembered - it worked. Well
and the question settled itself.
Hello Conan
Con> For example, in i8272, as far as I remember, the track read command works
Con> is fine, so what do we get from this?
As it turned out, no, when reading a track with the “read track” command on the i8272
synchronization failures occur after the GAP field following the sector data
(intersector space), while the address marker of the next sector is read
incorrect (all bytes are corrupted), a second synchronization failure also occurs on
the boundary of the sector address marker and the sector data field (where the field goes
synchronization of 12 zeros).
This error is fundamentally different from what happens on the VG93, because on
i8272 synchronization failure does not depend on the data in the sector, but always occurs on
sector boundary, and synchronization can be restored after several
sectors.
Why exactly the synchronization fails must be clarified separately,
it seems that instead of data pulses, the controller accepts pulses as data
synchronization (shift by half a bit interval).
Hello, CHRV
CHR> By default, the PC drive installed as "A" is visible on the Spectrum as
CHR> "B". And if it doesn’t “grunt”, check for 12v.
And if there is no 12V, then accept my congratulations - you have already burned 2 VGshki.
Hello deathsoft
I have had situations like this several times (I don’t know if they have anything to do with
this topic): after writing to a floppy disk, the file table shifted by one
byte. And the disk, of course, stopped being read by tr-dos. But by downloading any
disk editor, and by moving the file table into place, you could return everything to
ass
Hello, Ivan
> I had such situations several times (I don’t know if they have
> related to this topic): after recording to a floppy disk, a shift occurred
> file tables per byte. And the disk, of course, stopped being read
> tr-dos. But, by loading any disk editor and moving the table
> files in place, everything could be returned to the back.
This is not at all. Here we are talking about a shift by half a BIT interval. And not
byte.
Hello MegaMyth
Of course he did. And I even actively used it.
Hello MegaMyth
Meg> Has anyone ever held an 8-inch disk in their hands???
It's lying in my closet at home. Looks like 5.25", only the size of half a sheet
A4
Hello Conan
Con> I don’t know how rare or expensive it is
Most likely rare, because The datasheet is scanned, and the description says 5/25 and 8
inches... Who finally held an 8-inch disk in his hands???